The SKELETAL System. The framework of bones and cartilage which protect organs, and provides a lever system that allows locomotion.

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1 The SKELETAL System The framework of bones and cartilage which protect organs, and provides a lever system that allows locomotion.

2 Functions of the Skeletal System Support Protection Movement Facilitation Mineral Storage and Homeostasis Hematopoiesis Storage of Energy

3 Types of Bone Cells Osteoblasts deposit mineral salts and collagen fibers Osteocytes maintain bone tissue Osteoclasts break down bone tissue

4 Bone Cells

5 Ossification the process by which bones form in the body (Osteogenesis) the replacement of pre-existing connective tissue with bone Intramembranous Ossification Membranes ----> Bone (Periosteum - Width-wise Growth) Endochondral Ossification Cartilage ----> Bone (Epiphyseal Plate - Length-wise Growth)

6 Intramembranous Ossification

7 Endochondral Ossification

8 Homeostasis and Bone Remodeling Bones are constantly undergoing ossification and remodeling Replacing old bone matrix with new bone matrix bone reabsorption (osteoclasts) bone deposition (osteoblasts) Allows injured or worn out bone to be replaced Compact bone tissue is formed by the reorganization of spongy bone tissue

9 Types of Bones Long Bones Short Bones Flat Bones Irregular Bones Sesamoid Bones (not a classification used by all anatomists)

10 Types of Bones

11 Long Bones Greater length than width Have a distinct diaphysis and a variable number of epiphysis Slightly curved for strength Examples: humerus, ulna, radius, femur, tibia, fibula, metacarpals, metatarsals, phalanges

12 Short Bones Cube-shaped bones Nearly equal in length and width Spongy texture on inside of the bone Examples: carpal and tarsal bones

13 Flat Bones Generally thin and flat Compact bone on anterior and posterior surfaces with spongy bone in the middle Provides protection to organs Large surface area for muscle attachment Examples: cranial bones, sternum, scapula, ribs

14 Irregular Bones Complex shaped bones Cannot be classified into other categories Vary in the amount of spongy and compact bone Examples: vertebrae, facial bones, patella

15 Long Bone Structure Periosteum the outer covering Diaphysis - shaft of a long bone Epiphysis - ends of a long bone Medullary Cavity contains marrow Red Marrow where blood cells are produced. Yellow Marrow where fat is stored

16 Articular Cartilage hyaline cartilage found at the ends of long bones to reduce friction during movement. Endosteum the lining of the medullary cavity. Compact Bone densely packed osteocytes to provide strength to the bone.

17 Spongy bone loosely packed osteocytes which help to reduce the weight of the bone and form the red marrow.

18 Long Bone Structure

19 Proximal End of a Long Bone

20 Epiphyseal Plate

21 Classification of Bones Compact Bone (Dense Bone) little space between the solid components of bone Spongy Bone (Trabecular Bone) made up of an irregular network of thin plates of bone with many intercellular spaces called trabeculae (spicules) spaces between trabeculae filled with red bone marrow responsible for hematopoiesis

22 Spongy Bone Structure

23 Compact Bone

24 Bone Markings Foramen - an opening or hole in a bone Meatus - a tube-like passageway within a bone Sinus - a space within a bone lined with mucus membrane that reduces the weight of a bone Fossa - a depression or groove on a bone

25 Bone Markings Condyle - Knuckle - a large rounded prominence on a bone Tuberosity - an elevated, rounded, usually roughened area of a bone Trochanter - a large blunt process found only on the femur Tubercle - a small rounded process

26 Bone Markings Process - any projection from the surface of a bone

27 Suture and Fontanel Sutures are the joints between the skull bones. They fuse together between the ages of 18 months old and 3 years. Fontanels are the soft, membranous spots of a baby s skull that allows for brain growth and the delivery of the fetus through the birth canal.

28 Skull Lateral View

29 Divisions of the Skeleton Axial Skeleton - bones that lie along the long axis of the body. Includes the skull, hyoid bone, sternum, ribs, and vertebrae. Appendicular Skeleton - bones of the extremities.

30 Bones of the Skeletal System

31 The Axial Skeleton

32 Axial Skeleton 80 Bones Skull Hyoid Bone Vertebral Column Sternum Ribs

33 Axial Skeleton

34 Location of Basic Skull Bones Mandible Maxilla Zygomatic Frontal Parietal Occipital Sphenoid

35 Location of Basic Skull Bones Ethmoid Hyoid Temporal Mastoid Process

36 Skull Lateral View

37 Skull Posterior Vier

38 Cranial Bones (8) Frontal Bone Parietal Bones (2) Temporal Bones (2) Occipital Bone Sphenoid Bone Ethmoid Bone

39 Skull Anterior View

40 Skull Lateral View

41 Skull Sagittal View

42 Skull Inferior View

43 Skull Transverse Section

44 Frontal Bone Forms the forehead Forms the roof of the orbits (eye sockets) Forms most of the anterior portion of the cranial floor

45 Parietal Bones (2) Form the greater portion of the sides and roof of the cranial cavity

46 Temporal Bones (2) Form the inferior sides of the cranium and part of the cranial floor Temporal bone landmarks: Zygomatic Process Mandibular Fossa External Auditory Meatus Mastoid Process Styloid Process

47 Occipital Bone The posterior part and prominent portion of the base of the cranium Occipital bone landmarks: Foramen Magnum Occipital Condyles External Occipital Protuberance

48 Sphenoid Bone Bone situated in the middle part of the base of the skull Shaped like a bat Only bone that connects to all other cranial bones Sphenoid bone landmarks: Body - Sella Turcica Greater Wings -Sphenoid Sinuses

49 Sphenoid Bone

50 Ethmoid Bone Light, spongy bone located in the anterior floor of the cranium between the orbits Makes up much of the structure of the nasal cavity Ethmoid bone landmarks: Lateral Masses (Labyrinths) Ethmoid Sinuses - Crista Galli Perpendicular Plate -Cribriform Plate Superior Nasal Conchae Middle Nasal Conchae

51 Ethmoid Bone

52 Facial Bones (14) Nasal Bones (2) Maxillae (2) Zygomatic Bones (2) Lacrimal Bones (2) Palatine Bones (2) Inferior Nasal Conchae (2) Vomer Mandible

53 Facial Bones

54 Zygomatic Bones (2) cheek bones form the prominences of the cheeks and the floor and outer walls of the orbits Zygomatic bone landmarks: temporal processes zygomatic arches

55 Maxillary Bones (2) Pair of bones that unite to form the upper jaw Articulate with every bone of the face except the mandible Maxillary bone landmarks: Alveolar Processes Alveoli Palatine Processes - horizontal projection from the maxillae that forms the anterior three fourths of the hard palate Cleft Palate - Cleft Lip

56 Facial Bones Sagittal Section

57 Mandible (Lower Jaw) Bone Largest and strongest bone in the face The only moveable skull bone Articulates with the temporal bone to form the Temporal Mandibular Joint (TMJ)

58 Mandibular Landmarks Body - front and sides of the bone Rami - perpendicular portions of bone Angle Condylar Processes - joint Coronoid Processes - muscles Mandibular Notch Alveolar Processes and Alveoli Mental Foramen - front/body Mandibular Foramen - posterior ramus Mandibular Canal

59 Mandible

60 Hyoid Bone U-shaped bone suspended from the styloid processes by ligaments Only bone in the body that doesn t directly articulate with another bone Located between mandible and larynx Supports the tongue and provides point of attachment for some tongue and neck muscles

61 Hyoid Bone

62 The Vertebral Column (Spine) Together with ribs and sternum provide about two-fifths (40%) of the height of the body Composed of 33 (26) different bones Encloses and protects the spinal cord Supports the head Lower vertebrae supports the weight of the entire upper body

63 Vertebrae Bones of the vertebral column Cervical vertebrae (7) - neck Thoracic vertebrae (12) - ribs Lumbar vertebrae (5) - lower back Sacral vertebrae (5) - pelvic bones Coccygeal vertebrae (4) - tail bone Intervertebral Foramina - openings between the vertebrae for nerve exit

64 Vertebral Column

65 Intervertebral Discs Discs of fibrocartilage found between the vertebrae from C1 to the sacrum Functions to absorb shock Allows for the multi-directional motion between each vertebrae Annulus Fibrosis - outer fibrous ring Nucleus Pulposus - inner, soft pulpy portion of the intervertebral discs

66 Herniated Discs (Slipped Discs) Rupture of the fibrocartilage discs Usually caused by compression forces Usually occurs between L4 and L5 or L5 and the 1st Sacral Vertebrae Disc protrudes and exerts pressure on spinal nerves To decrease risk of herniated discs: 1. maintain optimal body weight 2. strengthen abdominal muscles 3. increase lower back flexibility

67 Herniated Disc

68 Spina Bifida congenital defect where the neural arch fails to unit usually involves the lumbar vertebrae symptoms may be mild to severe usually results in paralysis partial or complete loss of bladder control absence of reflexes can be diagnosed during pregnancy by sonography, amniocentesis, blood tests

69 Curvature of the Spine Increases strength of the spine Helps maintain balance Dissipates vertical shock Protects spinal column from fracture Anterior Curves (Secondary Curves) Cervical Vertebrae -Lumbar Vertebrae Posterior Curves (Primary Curves) Thoracic Vertebrae -Sacral Vertebrae

70 Curvature of the Spine

71 Abnormal Curvatures of the Spine Scoliosis - lateral curvature of the spine usually in thoracic and lumbar region Kyphosis - hunchback/humpback exaggeration of thoracic curvature Lordosis - swayback (sprinters butt) exaggeration of lumbar curvature

72 Abnormal Curvatures

73 The Appendicular Skeleton

74 Appendicular Skeleton 126 Bones clavicle scapula humerus ulna radius carpals metacarpals phalanges pelvis femur patella tibia fibula tarsals metatarsals phalanges

75 Appendicular Skeleton

76 Joints (Articulations) The points of contact between bones, between bones and cartilage, or between teeth and bones.

77 Structural Classification of Joints Classification of joints based upon how they are held together Fibrous Joints held together by fibrous connective tissue Cartilaginous Joints held together by cartilage Synovial Joints joint enclosed within a synovial or joint capsule

78 Synovial Joints Enclosed within a joint or synovial capsule fibrous capsule - outer layer attaches to periosteum of bone synovial membrane - inner layer secretes synovial fluid Space between the ends of articulating bones called a synovial space End of articulating bones are covered with hyaline (articular) cartilage

79 Typical Synovial Joint

80 Menisci Pads of fibrocartilagenous discs found between bony surfaces in some joints Allows the bones to fit together better Maintains the stability of the joint Absorbs shock Directs the flow of synovial fluid to areas of greatest friction

81 Bursae Sac-like structures that resemble joint capsules situated within body tissues Function like ball-bearings Reduces friction between bones and soft tissues Reduces friction between bones and skin

82 Knee Joint

83 Shoulder Joint

84 Shoulder Joint

85 Hip Joint

86 Tendons and Ligaments Tendons - connect muscle to bone A band or cord of dense fibrous connective tissue extending from a muscle to a bone for attachment Ligaments - connect bone to bone A band or cord of dense fibrous connective tissue extending from one bone to another bone to provide a joint with structural stability

87 Osteoarthritis Degenerative joint disease associated with aging Usually preceded by traumatic joint injury Characteristics: degeneration of articular cartilage development of bone spurs usually effects large joints (knees, hips, etc) Treatment: rest - removal of bone spurs joint replacement

88 Osteoporosis Decrease in bone mass and increased susceptibility to fractures.

89 Osteoporosis Contributing Factors Decreased estrogen production Poor nutritional status Low activity levels Weight Smoking Drugs and alcohol consumption Gender/race/hereditary factors

90 Osteoporosis - Treatment Calcium supplementation Estrogen Replacement Therapy Weight-bearing exercise Steroid treatment therapy